Machine unit comprising a drive and a machine

ABSTRACT

The invention relates to a high power machine unit. Said invention is characterized by the following features: a drive which has an output shaft; a machine which has a drive shaft; a converter ( 3 ) which is connected between drive and machine and can be filled and emptied; having a toothed clutch ( 4 ) which can be engaged and disengaged and is connected in parallel with the converter ( 3 ); one half ( 4.1 ) is firmly connected to the output shaft of the drive so as to rotate with it; the other half ( 4.2 ) of the clutch is firmly connected to the drive shaft of the machine so as to rotate with it.

[0001] The invention relates to a machine unit comprising a drive and amachine. Said invention relates in particular to a machine unit in whichthe drive is an electric motor or a gas turbine and the machine is acompressor. It concerns extraordinarily high powers which are of theorder of magnitude of 20 megawatts and above. Because of these extremelyhigh power, the machines also have extraordinarily high revolvingmasses, which of course in turn lead to particular problems.

[0002] The requirements on the machine unit of the aforementioned type,in particular comprising a gas turbine and a compressor, are thefollowing:

[0003] the compressor must be started up in a way without the drivebeing overloaded

[0004] the compressor must be run up to a rotational speed which isequal to the rotational speed of the drive, that is to say the twomachines must run in synchronism with each other

[0005] after reaching synchronous running, a direct mechanical driveconnection must be produced between drive and machine

[0006] in some machine units of the aforementioned type, in particularcomprising a gas turbine as drive and a compressor as machine, it may benecessary to allow the gas turbine to run continuously, specificallyeven when the compressor is switched off.

[0007] In the case of smaller machine units comprising drive andmachine, clutches subject to slip, for example friction clutches orplate clutches, can be connected between these two machines at lowrotational speeds. However, such clutches can be used only in the caseof low powers and small masses, which are a fraction of the value of themachine units mentioned here. In the case of machine units with theaforementioned extremely high powers and rotational speeds, the use ofsuch clutches is ruled out, however.

[0008] The invention is based on the object of providing a machine unitcomprising a drive, a machine and a transmission element connectedbetween these two, in particular comprising a gas turbine and acompressor, which is designed for extremely high powers and rotationalspeeds, with which the machine can be started up reliably and gently forthe drive, in which the drive and the machine can be run up tosynchronous rotational speeds, and where the drive can continue to runalthough the machine is stopped.

[0009] This object is achieved by the features of claim 1.

[0010] The inventors have therefore found a perfect solution for theproblem while solving all the aforementioned sub tasks.

[0011] The converter according to the invention can be filled andemptied. One half of the toothed clutch is firmly seated on the driveshaft, and therefore on the pump wheel, so as to rotate with it, whilethe other half of the clutch is firmly seated on the output shaft, andtherefore on the turbine wheel, so as to rotate with it. The clutch is aswitchable sliding clutch, in which the two halves of the clutch can bebrought into engagement by means of displacement in the axial direction.

[0012] Start up is carried out as follows, illustrated using the exampleof a machine unit comprising a gas turbine and a compressor:

[0013] (1) First of all, the gas turbine is started; the compressor isstationary.

[0014] (2) The converter is filled.

[0015] (3) The compressor is run up by the drive on account of theconverter filling and with appropriate adjustment of the guide vanes ofthe converter, specifically until synchronous running with the drive isachieved.

[0016] (4) The presence of synchronous running is registered by means ofsensors.

[0017] (5) The toothed clutch is then engaged. After the toothed clutchhas been engaged, torque is transmitted from the gas turbine to thecompressor over two paths, firstly on the path via the converter andsecondly via the path via the toothed clutch. The two force flows runparallel to each other.

[0018] (6) The converter is then emptied, so that only the toothedclutch still transmits torque from the gas turbine to the compressor.

[0019] During shutdown, there are two possible ways of operating themachine unit.

[0020] Possibility A:

[0021] (1) The gas turbine is switched off and run downs more or lessslowly with the compressor.

[0022] (2) The clutch is disengaged, which can be done by means ofdeliberate intervention or by an automatic mechanism.

[0023] (3) Drive and compressor come to a standstill, uncoupled fromeach other.

[0024] Possibility B:

[0025] (1) The empty converter is filled with operating medium again.

[0026] (2) The clutch is disengaged.

[0027] (3) The converter is emptied. Although the gas turbine continuesto run, no more torque is transmitted to the compressor, so that thelatter comes to a standstill.

[0028] Possibility B can be particularly advantageous. Applications canbe conceived in which the compressor is used only intermittently, butthe gas turbine is to continue to run for reasons connected with the gasturbine process.

[0029] The invention is explained in more detail using the drawing, inwhich the following are illustrated in detail:

[0030]FIG. 1 shows a substantial part of a machine unit according to theinvention, namely a converter according to the invention and a toothedclutch according to the invention.

[0031]FIG. 2 shows an enlarged detail from the subject of FIG. 1 in thearea of converter and toothed clutch.

[0032] Of a machine unit comprising a gas turbine and a compressor, FIG.1 shows only the force transmission unit located between these two,comprising the converter 3 and the toothed clutch 4. Converter 3 andtoothed clutch 4 are therefore connected between the gas turbine, notshown here, and the compressor, not shown here.

[0033] Converter 3 and toothed clutch 4 are connected in parallel witheach other. Both the converter 3 and the toothed clutch 4 can transmittorque from the converter input shaft 1 to the converter output shaft 2in each case on their own but also jointly.

[0034] Converter 3 can be filled and emptied. It comprises a pump wheel3.1 and a turbine wheel 3.2. It further comprises a stationary guidevane wheel 3.3 and an adjustable guide vane 3.4.

[0035] The pump wheel 3.1 of the converter 3 is firmly connected to theinput shaft 1 so as to rotate with it. The turbine wheel 3.2 of theconverter is firmly connected to the output shaft 2 so as to rotate withit.

[0036]FIG. 2 reveals the relationships in the area of converter andtoothed clutch in more detail. The toothed clutch 4 comprises two clutchhalves. One half of the clutch—a pinion 4.1—is firmly connected to theinput shaft 1 so as to rotate with it. The other half an internal gear4.2—is firmly connected to the output shaft 2 of the compressor so as torotate with it. Internal gear 4.2 can be displaced to the left in FIG.2. If this displacement is made, the clutch 4 is therefore engaged.

[0037] A connection 5 for control oil is provided. Through saidconnection, control oil can be introduced into the interior of theclutch housing, specifically in such a way that it acts on a piston 4.3which in turn displaces the internal gear 4.2 to the left. A valve, notillustrated here, is assigned to the connection 5.

[0038] In conjunction with the actuation of the clutch, a set of disksprings 6 is important—see FIG. 1. While control oil displaces thepiston 4.3 to the left when it is let into the connection 5, and theclutch 4 therefore engages, the disk springs 6 attempt the opposite.They have a tendency to disengage the clutch 4.

[0039] As described above, during the starting operation, synchronism isproduced between the gas turbine and the compressor and therefore alsobetween the input shaft 1 and the output shaft 2. The fact thatsynchronism is present is registered by sensors not shown here. At thisinstant, the aforementioned valve belonging to the control oilconnection 5 is opened. Control oil enters, acts on the piston 4.3 anddisplaces the internal gear 4.2 to the left, so that the clutch 4 isengaged. It remains engaged as long as the pressure of the control oilremains on the piston 4.3. For this reason, the valve upstream of theconnection 5 is kept open for as long as it is wished to keep the clutchengaged.

[0040] If it is desired to disengage the clutch 4, then theaforementioned valve belonging to the control oil connection 5 isclosed, and at another point care is taken that control oil can escape,for example by opening an outlet 7—see FIG. 2. If these conditions arepresent—control oil feed at connection 5 closed and control oildischarge 7 opened—then only the springs 6 act on the piston 4.3 via arod 6.1, so that the piston 4.3 is moved to the right in FIG. 2, andtherefore so is the internal gear 4.2. The clutch is disengaged, and nomore torque is transmitted via the clutch 4.

[0041] However, the converse function is also conceivable: for example,engagement can be brought about by means of spring force anddisengagement again by means of hydraulic pressure.

1. High power machine unit; 1.1 comprising a drive which has an output shaft; 1.2 comprising a machine which has a drive shaft; 1.3 comprising a converter (3) which is connected between drive and machine and can be filled and emptied; 1.4 having a switchable toothed clutch (4), which is connected in parallel with the converter (3); 1.5 one half (4.1) of the clutch is firmly connected to the output shaft of the drive so as to rotate with it; 1.6 the other half (4.2) of the clutch is firmly connected to the drive shaft of the machine so as to rotate with it.
 2. The machine unit as claimed in claim 1, characterized by the following features: 2.1 the toothed clutch (4) is assigned a switching actuator; 2.2 the switching actuator has a hydraulic unit comprising a piston (4.3) and a cylinder, which can be acted on with the effect of engaging the toothed clutch (4) by means of a pressure medium which can be applied via a medium connection (5); 2.3 a return spring (6) is provided, which acts with the effect of disengaging the toothed clutch (4).
 3. The machine unit as claimed in claim 1, characterized by the following features: 3.1 sensors are provided for registering the rotational speeds of drive and machine; 3.2 a device is provided for cutting off the connection (5) of the medium and for letting the medium out of the hydraulic unit.
 4. The machine unit as claimed in one of claims 1 to 3, characterized in that the drive is a gas turbine and the machine is a compressor. 